[xmlsec] Using asymmetric keys without 'app'?

[Jacob Fugal]

Hi, I'm having some trouble figuring out how to load an asymmetric key
from a file (e.g. a DSA private key) to use for signing when not using
the xmlSecCryptoApp* methods. The problem I see is that the
xmlSecKeyReadBinaryFile function uses in turn xmlSecKeyDataBinRead,
which requires a valid binRead handler for the specified
xmlSecKeyDataId (in my case xmlSecKeyDataDsaId). xmlSecKeyDataDsaId
has a value of NULL for the binRead handler.

Is there some other way aside from xmlSecCryptAppLoadKey to load a DSA
private key from a file?

Thanks,

Jacob Fugal